646
FXUS65 KBYZ 291437
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
837 AM MDT FRI MAY 29 2026
KEY MESSAGES
- HOT TODAY. RIVER FLOWS INCREASE DUE TO MOUNTAIN SNOWMELT. NO
FLOODING IS EXPECTED AT THIS TIME.
- SLIGHT CHANCE OF LATE DAY SHOWERS AND THUNDERSTORMS TODAY.
ERRATIC WIND GUSTS UP TO 50 MPH ARE THE MAIN THREAT.
- WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY ALONG WITH A COOLING
TREND THIS WEEKEND; EXACT DETAILS REMAIN UNCERTAIN.
- ACCUMULATING SNOW IS FORECAST OVER 9000 FT THIS WEEKEND. WINTER
CONDITIONS MAY IMPACT THE BEARTOOTH HIGHWAY (MODERATE CHANCE).
- MARGINAL RISK (1/5) FOR STRONG TO SEVERE THUNDERSTORMS OVER
SOUTH-EASTERN MONTANA AND NORTH-EASTERN WYOMING SATURDAY.
DISCUSSION
NEXT 7 DAYS (THROUGH THURSDAY)...
SATELLITE IMAGERY SHOWS THE PERSISTENT UPPER LEVEL PATTERN STILL
IN PLACE, WITH AN UPPER LOW OVER CALIFORNIA AND HIGH PRESSURE
RIDGE TO THE EAST. HIGH TEMPERATURES WILL RANGE FROM THE 80S TO
LOWER 90S TODAY, WARMEST OVER THE EAST. EAST TO SOUTHEAST WINDS
WILL CONTINUE TO BE BREEZY NEAR THE DAKOTAS BORDER WHERE
WIDESPREAD GUSTS OF 20 TO 40 MPH CAN BE EXPECTED INTO THE EVENING.
THE UPPER LOW ON THE WEST COAST IS PROGGED TO BEGIN TO SHIFT EAST
THRU NEVADA AND UTAH THROUGH THE DAY WITH A NEGATIVE TILT. HIGH
PRESSURE ALOFT WILL STILL REMAIN OVER OUR CWA...BUT DIURNAL
DESTABILIZATION WILL START TO PRODUCE SOME ISOLATED CONVECTION IN
THE AFTERNOON. A FEW THUNDERSTORMS COULD PRODUCE SOME BRIEF
MODERATE/HEAVY RAIN AND SMALL HAIL WITH MUCAPE PROGGED AT 500-1000
J/KG...BUT PWATS ARE PROGGED TO REMAIN UNDER AN INCH AND FORCING
AND SHEAR REMAIN WEAK...SO MOST STORMS WILL REMAIN GARDEN VARIETY.
SOUNDINGS DO SUPPORT SOME STRONG WIND GUSTS TO 50 MPH, ESPECIALLY
WITH ANY CELLS THAT FORM OVER OUR WEST.
THE UPPER LOW IS EXPECTED TO LIFT NORTH THROUGH WYOMING SATURDAY
AND INTO MONTANA SATURDAY NIGHT AND SUNDAY. THIS WILL RESULT IN
AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS. SATURDAY
BECOMES A DAY OF POTENTIALLY HEAVY RAIN AND SEVERE WEATHER OVER
OUR CWA. THE EXACT TRACK OF THE UPPER LOW AND SETUP OF ASSOCIATED
SURFACE FEATURES WILL DETERMINE IF AND WHERE THE BEST POTENTIAL
FOR SEVERE THUNDERSTORMS OCCUR. AT THIS TIME, THE SURFACE LOW IS
EXPECTED TO DEVELOP NEAR SHERIDAN, WY ALONG THE MT/WY BORDER
EXTENDING NORTHWARD JUST WEST OF MILES CITY. EAST OF THIS BOUNDARY
IS GENERALLY WHERE A FAVORABLE ENVIRONMENT WILL EXIST WITH
INCREASING SHEAR AND MID LEVEL FLOW. WOULD NOT BE SURPRISED TO SEE
THE ATMOSPHERE UNZIP OVER OUR FOUR EASTERN COUNTIES (CUSTER,
FALLON, POWDER RIVER, CARTER) SATURDAY AFTERNOON WITH POTENTIAL
FOR LARGE HAIL, HEAVY RAIN. FURTHER WEST OVER SOUTH CENTRAL MT,
STRONG UPPER FORCING AND INCREASING MOISTURE SHOULD PRODUCE
NUMEROUS SHOWERS AND THUNDERSTORMS TO DEVELOP AND COME OFF THE
HIGHER TERRAIN. A FEW STORMS IN THIS AREA MAY PRODUCE HEAVY
DOWNPOURS AND MARGINALLY SEVERE HAIL (QUARTER SIZE). AGAIN,
DETAILS ARE UNCERTAIN AND FOLKS ARE URGED TO BE AWARE OF THE
CHANGING SKY CONDITIONS AND FORECAST. SPC CURRENTLY HAS A MARGINAL
RISK OF SEVERE WEATHER FOR OUR EAST SATURDAY. PWATS SATURDAY WILL
JUMP OVER AN INCH FOR MANY LOCATIONS AND WITH STEEP LAPSE RATES
AND UPPER FORCING WE MAY SEE POCKETS OF MODERATE TO HEAVY RAINFALL
RATES.
WPC DOES CURRENTLY HAVE MUCH OF OUR AREA INCLUDED IN A SLIGHT
RISK FOR EXCESSIVE RAINFALL. WHILE THE RISK FOR FLOODING REMAINS
LOW OVERALL AT THIS TIME, THERE COULD BE LOCALIZED CONCERNS DUE TO
NEAR STATIONARY THUNDERSTORMS AND HEAVY RAINFALL ON RECENT BURN
SCARS. WE WILL CONTINUE TO CLOSELY MONITOR THE FLOODING POTENTIAL.
PEOPLE NEAR BURN SCARS AND FLOOD PRONE AREAS SHOULD BE ALERT AND
THINK ABOUT A PLAN IF FLOODING OR DEBRIS FLOWS OCCUR.
THE PROBABILITY FROM SATURDAY THROUGH MONDAY FOR 0.5 INCHES OF
PRECIPITATION RANGES FROM (40-90%, GREATEST OVER WESTERN AND
CENTRAL AREAS), WITH PROBABILITIES FOR AN INCH OR MORE OF
PRECIPITATION RANGING FROM 25% IN THE EAST TO 70% WEST. SNOW
LEVELS LOOK TO FALL NEAR 9,000 FEET, WITH POTENTIAL FOR SEVERAL
INCHES OF SNOW OVER THE HIGHEST PEAKS, INCLUDING NEAR PORTIONS OF
THE BEARTOOTH HIGHWAY.
MUCH OF THE THUNDERSTORM ACTIVITY WILL MOVE NORTH AND EAST OF THE
AREA SATURDAY NIGHT. HOWEVER, WITH THE UPPER LOW PARKED RIGHT
OVER OUR AREA SUNDAY INTO MONDAY, LINGERING SHOWERS AND EMBEDDED
THUNDER IS A GOOD BET, ALTHOUGH THE FLOW PATTERN MAY RESULT IN A
DRY SLOT FORMING OVER OUR AREA BY SUNDAY EVENING IF THE UPPER LOW
DOES MANAGE TO SLIDE FURTHER NORTH. AS THE UPPER LOW LIFTS SLOWLY
INTO CANADA BY TUESDAY, WE MAY REMAIN IN A CYCLONIC FLOW PATTERN
WITH A CHANCE OF SHOWERS, BUT FORCING WILL BE WEAKER AND PWATS
DROP...SO CHANCE OF STRONG STORMS AND HEAVY RAIN DECREASE.
TEMPERATURES ARE FORECAST TO DROP INTO THE UPPER 60S TO 80S
SATURDAY, TO THE 60S TO 70S SUNDAY THROUGH TUESDAY. TEMPERATURES
NUDGE A BIT HIGHER FOR WEDNESDAY, WITH HIGHS IN THE 70S TO AROUND
80, BUT THERE IS A CHANCE COOLER WEATHER LINGERS INTO MIDWEEK AS
ENSEMBLES SHOW A WIDE SPREAD OF SOLUTIONS. BT
AVIATION
UPDATED 1430Z. ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON
AND EVENING WILL BE CAPABLE OF PRODUCING ERRATIC WIND GUSTS UP TO
45KTS, MODERATE RAINFALL AND LOCALIZED/BRIEF MVFR. VFR WILL
PREVAIL OTHERWISE TODAY. LOOK FOR MORE WIDESPREAD SHOWERS &
THUNDERSTORMS TO DEVELOP SATURDAY. EXPECT BREEZY SE WINDS TO
CONTINUE TODAY OVER FAR EASTERN MONTANA AROUND KBHK AND K97M. JKL
PRELIMINARY POINT TEMP/POPS
TDY SAT SUN MON TUE WED THU
-------------------------------------------------------
BIL 093 061/076 054/063 048/065 046/073 048/076 051/079
2/T 39/T 97/T 54/T 21/B 11/B 22/T
LVM 085 051/066 044/055 039/061 038/069 040/075 044/076
2/T 49/T +9/T 75/T 22/T 12/T 34/T
HDN 094 057/079 052/066 045/067 043/074 046/077 048/080
2/T 28/T 98/T 63/T 22/T 11/B 21/B
MLS 096 061/085 055/074 048/068 047/074 049/076 050/078
0/U 25/T 88/T 64/W 33/T 21/B 22/T
4BQ 094 059/083 054/071 047/068 046/075 048/076 050/078
0/B 26/T 78/T 63/T 32/W 21/B 23/T
BHK 089 055/081 053/075 046/069 045/074 047/076 048/077
0/N 18/T 78/T 74/T 53/T 32/T 23/T
SHR 088 051/075 046/065 041/066 040/073 041/076 043/077
2/T 37/T 89/T 76/T 22/T 12/T 24/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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